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AREA SOURCE BOILER RULE 

Comments:

 Page 18, Item B.4: It is stated that a boiler is not temporary if it is moved from one location to 

another in an attempt to circumvent the residence time (maximum consecutive 12 months) 

requirements of the definition of a temporary boiler. Further clarification of this requirement 

would be very helpful. If a facility requires a boiler for 10 months of a year and decides to rent a 

mobile unit, would it be allowed to use the same mobile unit at some other location within the 

same plant or another plant in the system?

 Revise the emission limit tables by changing “Particulate Matter” to “Particulate Matter 

(Filterable)” as was done in the CISWI rules so that it will be clear that the limits do not include 

condensable particulate matter.

 Change “less than” to “equal to or less than” in section VI end of first paragraph (page 57) and 

in two places in 63.11223(d). Rationale: The proposal is not consistent as to whether an oil-fired 

unit rated 5 MMBtu/hr or more is subject to a biennial tune-up or five-year tune-up. At the end 

of the paragraph in section IV G.1. (page 24) it says "We are proposing ... to change the 

requirement for subsequent tune-ups only for oil-fired boilers equal to or less than 5 MMBtu/hr 

to a tune-up once every 5 years." This is consistent with Table 2 to subpart JJJJJJ, items 4, 5, 8, 

and 9 (page 90) which indicates biennial tune-ups are required for units greater than 5 

MMBtu/hr and five-year tune-ups for units 5 MMBtu/hr and below. However at the end of first 

paragraph in section VI and in the proposed revision to 63.11223(d) (in two places) it refers to 

oil-fired units "less than 5 million Btu/hr". 

 Change definition of “fossil fuel-fired” to “fossil fuel-fired EGU” or delete this term and merge 

with the definition of EGU. Note: this comment is consistent with comments on the EGU. We 

suggest these definitions be consistent in all of the rules. We note that the definition of EGU was 

added to the major source rule but not the definition of “fossil fuel-fired.” Rationale: Definition 

of “fossil fuel-fired” does not seem to be necessary. If it remains it should probably be “fossil 

fuel-fired EGU.” The only place that term is used in the rule is in the definition of “electric utility 

steam generating unit (EGU)” which was also added. It does not seem appropriate to limit the 

definition of “fossil fuel-fired” to EGUs. Two options for addressing this comment follow:

Option 1: Consider changing as follows (some changes are to make the definition consistent with the 

draft EGU rule): 

Fossil fuel-fired EGU means an electric utility steam generating unit (EGU) that is capable of 

combusting more than 25 MW of fossil fuels. To be “capable of combusting” fossil fuels, an EGU 

would need to have these fuels allowed in their operating permits and have the appropriate fuel 

handling facilities on-site or otherwise available ( (e.g., coal handling equipment, including coal 

storage area, belts and conveyers, pulverizers, etc.; oil storage facilities). In addition, fossil fuelfired EGU means any EGU that fired fossil fuels for more than 10.0 percent of the average annual 

heat input in any 3 consecutive calendar years or for more than 15.0 percent of the annual heat 

input during any one calendar year after [COMPLIANCE DATE OF THE FINAL EGU RULE].
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Option 2: Alternatively, instead of adding this definition, recommend deleting the term “fossil fuelfired EGU” and merge the relevant text with the definition of EGU as follow (some changes are to 

make the definition consistent with the draft EGU rule):

Electric utility steam generating unit (EGU) means a fossil fuel-fired combustion unit of more than 25 

megawatts that serves a generator that produces electricity for sale. A fossil fuel-fired unit that 

cogenerates steam and electricity and supplies more than one-third of its potential electric output 

capacity and more than 25 megawatts electrical output to any utility power distribution system for sale 

is considered an electric utility steam generating unit. To be “capable of combusting” fossil fuels, an EGU 

would need to have these fuels allowed in their operating permits and have the appropriate fuel 

handling facilities on-site or otherwise available (e.g., coal handling equipment, including coal storage 

area, belts and conveyers, pulverizers, etc.; oil storage facilities). In addition, fossil fuel-fired EGU means 

any EGU that fired fossil fuels for more than 10.0 percent of the average annual heat input in any 3 

consecutive calendar years or for more than 15.0 percent of the annual heat input during any one 

calendar year after [COMPLIANCE DATE OF THE FINAL EGU RULE].

Fossil fuel-fired means an electric utility steam generating unit (EGU) that is capable of 

combusting more than 25 MW of fossil fuels. To be “capable of combusting” fossil fuels, an EGU 

would need to have these fuels allowed in their operating permits and have the appropriate fuel 

handling facilities on-site (e.g., coal handling equipment, including coal storage area, belts and 

conveyers, pulverizers, etc.; oil storage facilities).

Corrections:

 Page 69. Revise instructions for amendment 2 to clarify that paragraph (c) is being changed. Also 

the amended introductory text for 63.11195 says "(a) through (i) " but should say "(a) through (k)."

 Page 77. 63.11223(d) Change "oil-fire" to "oil-fired" in two places in this paragraph.

 Page 78. Revise instructions for amendment 11 to clarify that paragraph (a)(5) is being changed.

 Page 81. Revise instructions for amendment 12 to clarify that paragraph (g) is being added.

 Page 84: Revise instructions for amendment 13 to include the definitions added to the rule in the 

redline version.

 Page 91/92. Definition of Qualified Energy Assessor is followed by "mean" which should be changed 

to "means". The first part of the definition is awkward; too many prepositions. It appears that the 

entire change in the definition consists of changing "to opportunity" to "for opportunity” in the 

introductory sentence. Perhaps the sentence can be more simply stated as "(1) someone who has 

demonstrated capabilities to evaluate energy savings opportunities for steam generation and major 

energy using systems, including, but not limited to:"
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Major Sources

 Can EPA explain how it would establish a limited use subcategory based on a capacity factor 

approach (10% CF), rather than 10% of the time in a year? EPA does not know how to establish 

a subcategory based on capacity factor that meets the requirement of section 112(h), and 

therefore, EPA is maintaining the “10 percent of hours” approach.

 Define natural gas curtailment. Natural gas curtailment is already defined in the rule as “period 

of natural gas curtailment or supply interruption.”

 In the Background section that begins on page 11, EPA should consider providing a summary of 

the issues that it reconsidering in this action, to assist the public in understanding this rule. 

While the issues are too difficult to describe in a list, the EPA added a sentence at the end of the 

background section to point the reader to section V. The sentence is as follows: The issues upon 

which the EPA is soliciting comment are discussed in section V of this preamble.

 Page 15, 2nd Paragraph: This paragraph establishes the criteria under which a multi-fueled 

combustion unit would be subjected to either liquid or solid fuel-based emission limits for fuelbased pollutants. The criteria appear to cover only those units that co-fire liquid and solid fuels. 

Are there units in your database that co-fire liquid and gaseous fuels? Specifically, if a unit fires 

less than 10 percent liquid fuel and the rest as gaseous fuel, would it be covered under the 

emission limits for gas? Yes. The “Gas 2” subcategory is defined to include such units.

 Page 16, 2nd Paragraph: Same question for the combustion-based pollutants as in above Item 1.

Same answer as above.

 Pages 18 – 20, Table 1: We are requesting further clarifications on the following items:

o In several places, the emission limit for a particular pollutant and source subcategory is 

indicated by “NA.” It is not clear as to what “NA” stands for. For example, for HCl and 

Hg emission limits, it appears that the emission limits shown for existing solid fuel 

boilers may apply to all other subcategories of solid fuel boilers. However, for the 

existing biomass kiln-dried stokers, the same “NA” shown for the alternate CO CEMS 

limit, may mean no applicable emission limit. Please confirm. NA means not applicable. 

Changed several of the “NA” entries to “ND” to indicate that no data are available to 

develop a limit for that subcategory. NA and ND are now defined in the footnotes.

o A 3-run average test requirement (Note a) is shown for particulate matter and CO? 

Since this note does not appear for HCl and Hg, does it mean that a compliance test is 

not required for these two pollutants? It does not mean that. Added footnote “a” to the 

HCl and Hg columns.

o On Page 15, it is stated that a liquid-fueled unit firing less than 10 percent solid fuel 

would have to meet the required liquid fuel emission limits. Do these emission limits 

(e.g., for HCl and Hg) still apply, if this unit fires solid fuel only for a short period? Yes, as 

long as the annual heat input is maintained in such a way that meets the liquid fuel 

subcategory definition (all subcategories are defined on an annual heat input basis).
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 Page 24, 2nd Paragraph: It would be very helpful if the points of measurement for the pressure 

drop are defined, i.e., from what point to what point in the scrubber? Added “across the 

scrubber” to indicate where the pressure drop should be measured.

 Pages 17-21, Table 1: We understand the establishment of a compliance option that allows the 

use of CO CEMS as an alternative to CO stack testing and oxygen monitoring. If an affected 

source currently uses CO CEMS, it seems unreasonable to require that they install additional 

monitoring equipment for CO stack testing. However, we note that the CO CEMS limits appear to 

be very different in some instances than the CO stack testing limits (e.g., 1400 ppm versus 58 

ppm for Biomass Dutch Ovens for the CO CEMS and CO stack testing limits respectively). We 

request further information and explanation on the reasons and implications of these very 

different limits. The limits are based on the available data, and the data sets are different for the 

stack test limits and the CEMS limits. We are taking comment on an approach that would change 

many of the CEM-based limits, and also discuss incorporating autocorrelation into the CO CEMS 

analysis, which would incorporate additional variability where we have significantly robust data 

sets.

 Pages 220-224, §63.7533 “Can I use emission credits earned from implementation of energy 

conservation measures to comply with this subpart?” While we understand EPA’s desire to 

recognize facilities that implement energy efficiency measures that improve the efficiency of or 

impact the steam required from affected units, we are concerned over the lack of guidelines and 

specific requirements for the emissions credits. Specifically, we are concerned with directing the 

source to create criteria for determining the energy savings from each measure implemented, as 

well as requiring an applicable delegated authority to review and approve this. We believe it will 

be difficult to adequately estimate the impact of many potential efficiency measures without 

detailed guidelines and requirements. We also question the validity of recognizing efficiency 

measures that may have been implemented as far back as 2008. It would seem that the 

establishment of an output-based emissions limit option itself would already incorporate the 

value of these past efficiency measures. We are concerned that the way this subpart is 

structured, it could a) create national inconsistency in how emissions credits are created and 

applied (possibly creating gaming), and b) burden the “applicable delegated authority” who do 

not have expertise on energy efficiency measures in industrial facilities. We recommend EPA 

explicitly take comment on the emission credit concept, how to administer it consistently 

across the country.

o Page 49: “Legal Authority for Emission Credits. One petitioner questioned the legal 

authority of the emission credit system and stated that it should be removed from the 

final rule. However, the petitioner provided no support for its position, and the EPA 

continues to believe that the emission credit system is legal as promulgated. Therefore, 

no changes are being proposed.” We request additional information from EPA on the 

legal authority for the emission credit system as proposed. Does EPA outline the legal 

rationale for these emissions credits somewhere else? Can this be explained again here?

While the specific legal rationale is not outlined, the general philosophy is that each unit 

meets the emission limits as required, but the credits allow for consideration of energy 

efficiency measures that have been implemented. Regardless, we have added language 

to specifically request comment on: (1) the overall concept of the emission credit 

provision, (2) how to administer it consistently across the country, and (3) available 
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guidelines to inform the delegated authority's decision to approve the implementation 

plan.

- In anticipation of public comments requesting health-based emissions limits for acid gases (and 

because this issue was raised in the petitions for reconsideration), we believe this proposed rule 

would be strengthened by clearly articulating EPA’s reasoning for not proposing health-based 

emissions limits for acid gases. We responded to the health-based emission limit comments in 

the preamble to the final rule, and no new information was provided in the petitions or 

supplemental data submittals in support of a health-based provision.

-

 Revise the emission limit tables by changing “Particulate Matter” to “Particulate Matter 

(Filterable)” as was done in the CISWI rules so that it will be clear that the limits do not include 

condensable particulate matter. This clarification would be consistent with the preamble which 

refers to “the filterable PM emission limits” on pages 46 and 115. OK

 Double check the alternate CO CEMS 10-day average emission limits. Many of the limits are 

higher than the 3-run average limit which would be expected. However, some of the limits are 

lower (some by a factor of 6). CEMS limits may not always be higher, depending on various 

factors including the testing conditions (load), use of supplemental fuels (potentially 

undocumented for some data sets), and the availability of data. Regardless, we are taking 

comment on a couple of approaches that would adjust many of the limits.

Corrections:

 Table 2 to subpart DDDDD: 1) In 4th column, delete “(lb per MMBtu of steam output)” from the 

heading row since limits in this column of the table are not all in these units. Done. 2) The 

sample volume in the last column of item 1a should probably be 120 liters (should match item 

1a of Table 1 to subpart DDDDD since the limits are identical). 120 liters is correct, and the value 

in table 2 has been fixed. 3) In the last column for item 10c, the footnote after D6784 should be 

b instead of a. Change made.

 Table 6 to subpart DDDDD: Based on alignment of methods for item 3, it is not clear if they all 

apply to both a and b or if the first method applies to item a and the rest to item b. They all 

apply to “a.” Format changed to clarify.

 Table 8 to subpart DDDDD: Delete the word “block” from item 7b. Done. Also item 11c should 

be 11b. Done.

 Table 10 to subpart DDDDD: Add “§” in front of 63.8(g). Done.

RIA

REGULATORY IMPACT ANALYSIS: NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR 

POLLUTANTS FOR INDUSTRIAL, COMMERCIAL, AND INSTITUTIONAL BOILERS AND PROCESS HEATERS

General Comment:

We appreciate EPA’s efforts to provide an update to the Boilers RIA. We appreciate the updated 

information provided at the beginning of the RIA. We request that the current organization be 

maintained, with the previous RIA included as an Attachment (e.g. Attachment A). For the updated 

material at the front, we’d suggest for both the costs and the benefits that the changes be delimited in 

the following way, and presented in a summary CBA table:

- Methodological/Estimate changes
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- Rule changes 

With the approach outlined above, it should be easier for the reader to understand how/why the costs 

and benefits estimates have changed. 

We are including the document with the February RIA as an appendix. We summarize the changes in 

paragraph form but don’t know how to provide the table mentioned. There are no methodology 

changes and relating estimate changes to particular rule changes is not possible because the underlying 

cost and emission changes are for the whole set of changes to the rule rather than individual changes.

Specific Comments

Section 2.1.3.8, Page 2-14, Table 2-10; Section 2.2.3.8, Page 2-30, Table 2-18; Section 2.3.3.5, Page 2-

47, Table 2-28; Section 2.4.3.9, Page 2-66, Table 2-39: The employment total is far higher than the total 

calculated by adding up the various columns. For example, in Table 2-39, employment totals 827,430, 

but adding up the various columns only results in around 300,000 employees. Therefore, unless there 

are around 500,000 employees in the 1,500+-employee category, then there is an error. There are 

around 500,000 employees in the 1,500+-employee category (550,000 in greater than 500 minus 28,025 

in 500 to 759, minus 18,119 in 750 to 999, and minus 28,338 in 1000 to 1499) from 

http://www2.census.gov/econ/susb/data/dynamic/0809/us_4digitnaics_emplchange_2008-2009.xls

and table 2-39 .

Section 4.1.2.4.1, Page 4-11, Table 4-3: Since the overall results of the Morgenstern et al. study are 

statistically insignificant, it seems more practical to not provide corresponding job estimates, but to 

simply indicate the overall employment impacts were found to be statistically insignificant. Because of 

the interest in employment EPA has used this study for a number of regulations to estimate the mean 

net employment and provided the 95% confidence interval results to reflect the high degree of 

uncertainty (the interval includes zero so we are showing we don’t know the sign of the effect but the 

interval itself is helpful when others give exaggerated claims of huge job changes well outside our 95% 

confidence interval.

Section 7.2.5, Page 7-14, top and bottom paragraphs: It seems a range for value of statistical life should 

be used rather than the mean value. Making this adjustment would provide an improved measure of 

uncertainty in the benefits calculations. As described in the RIA, EPA determined that a single, peerreviewed estimate applied consistently best reflects the advice it has received from the EPA’s 

independent Science Advisory Board until updated guidance on mortality valuation is available. The 

Agency continues its efforts to update its guidance on this issue.

Section 7.3, Page 7-21, Table 7-2 and Table 7-3: The table shows the estimated reductions in health 

incidences for both SO2 and Direct PM 2.5. Since some studies have found no significant effect of 

PM2.5 on mortality, perhaps zero should be included in the PM 2.5 and SO2 range (since SO2 is included 

because it is a precursor to PM 2.5), as Electric Power Research Institute has suggested. EPRI indicated: 

“Since some models in some studies do not find a statistically significant effect of PM2.5 on mortality, 

the effects range could even include zero...” (Source: EPRI PM2.5 Reductions and Impact on Premature 

Death: An EPRI perspective; Issue Brief 1018632.) In addition, the same EPRI briefing states the EPRIWashington University Veterans Study did not find any statistically significant mortality associations with 

PM2.5, but found some PM components that were significantly associated with mortality. The EPRI 

briefing goes on to say: “Of great significance for CAIR, this study did not find a significant association 

between the sulfate component of PM and mortality...if this study were used to derive estimates of 

health benefits attributable to reductions in SO2 emissions, the numbers would differ from those 
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derived from the Pope et al...some studies have shown that estimated impacts of PM diminish when 

other co-pollutants are considered in the analyses. If the co-pollutants are indeed associated with 

increased mortality and are correlated with PM levels, then the PM effects estimated from this single 

pollutant model approach can be biased upwards.”

EPA disagrees with this recommendation. The Integrated Science Assessment (ISA) for Particulate 

Matter (U.S. EPA, 2009), which was twice reviewed by the Science Advisory Board, concluded that there 

is a causal relationship between exposure to PM2.5 and premature mortality after reviewing the entire 

body of scientific evidence. In addition, the ISA also concluded that the scientific evidence is not yet 

sufficient to allow differentiation of effect estimates by particle type. This means that while some PM 

mixtures may be more toxic than other mixtures, the scientific literature does not support the 

commenter’s assertion that some particles are not toxic. Although we note this uncertainty in the RIA, 

we assume that all particles are equally toxic for the purpose of calculating benefits. This assumption 

was supported by the National Academies of Science and the Health Effects Subcommittee of the 

Advisory Council on Clean Air Compliance Analysis. 

Additionally, why does the study focus on the mortality estimates of fine particulate matter from two 

studies? Given that there are a number of studies available, these studies should be used to develop 

the estimates for the RIA. An EPRI study (Issue Brief 1018632, “PM2.5 Reductions and Impact on 

Premature Death: An EPRI Perspective”) includes the following statements.

“Since some models in some studies do not find a statistically significant effect of PM2.5 on 

mortality, the effects range could even include zero...” 

“The EPRI-Washington University Veterans study did not find any statistically significant 

mortality associations with PM2.5, but found some PM components that were significantly 

associated with mortality.”

“Of great significance for CAIR, this study did not find a significant association between sulfate 

component PM and mortality ... if this study were used to derive estimates of health benefits 

attributable to reductions in SO2 emissions, the numbers would differ from those derived from 

the Pope, et al study.”

“Some studies have shown that estimated impacts of PM diminish when other co-pollutants are 

considered in the analyses. If the co-pollutants are indeed associated with increased mortality 

and are correlated with PM levels, then the PM effects estimated from this single pollutant 

model approach can be biased upwards.”

As described in the RIA, EPA estimates avoided PM-related premature mortality based on risk 

estimates from the American Cancer Society cohort (Pope et al., 2002) and the Harvard Six Cities 

cohort (Laden et al., 2006) as well as providing mortalities estimates based on the results of an 

expert elicitation (Roman et al,2008) as a characterization of uncertainty. The choice of these 

studies was supported by the Health Effects Subcommittee of the Advisory Council on Clean Air 

Compliance Analysis. In addition, when EPA conducted an expert elicitation on the relationship 

between PM2.5 exposure and premature mortality in 2006, the experts placed most weight on 

the results of these two studies.
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Section 7.3, Page 7-22, Table 7-4: It would be useful to indicate the average (or a range) number of 

years for avoided premature mortality (i.e., on average, those with who would otherwise experience 

premature mortality, would be expected to live X number of years longer.)

EPA does not have the necessary data to estimate avoided life years lost for this rule. However, in the 

2006 PM NAAQS RIA, EPA estimated that the discounted average gain in life years is 10 years. In 

Hubbell (2006), the estimate of average undiscounted life years gained was 15.26 years.

Hubbell, Bryan J. 2006. “Implementing QALYs in the Analysis of Air Pollution Regulations,” 

Environmental and Resource Economics 34:365–384.

The following comments refer to the preamble for the major sources rule, but are also applicable to the 

area sources rule.

- On page 122, the preamble addresses the US trade deficit. For clarity, we recommend revising 

the sentence that reads, “The change in US surplus is now -1.93 billion dollars (2006$)” with the 

following sentence, “The increase in US trade deficit is now 1.93 billion dollars (2006$).” Done.

- In the discussion of economic impacts on page 124, over what time frame do the estimated 

employment changes occur and what is the primary driver for the estimated change in benefits?

- We are adding a sentence to page 124 about the time frame for employment.

- We will clarify in the preamble that the SO2 emission reductions increased because there are 

more units affected and the HCl limit was revised.

- On page 125, the preamble states, “These monetized benefits are approximately 23 percent 

higher than the final rule benefits due to the increase in SO2 emission reductions.” Are these 

net of the increased SO2 secondary emissions mentioned in the following section on secondary 

benefits? The increase in SO2 emission reductions from industrial boilers are separate from any 

secondary air impacts due to changes in electricity demand.

- How does EPA define the term “secondary air impacts” on page 127? Secondary air impacts are 

increases in emissions that result from the requirements of the rule from sources not regulated 

by the rule. Typically, these impacts are the expected air emissions from sources that provide 

energy to facilities that have increased energy demands that result from the rule (e.g., energy to 

power air pollution controls).

- Additionally, EPA notes on page 127 that it does not estimate an “increase in secondary air 

impacts for this final rule from additional electricity demand.” Does the RIA count the benefits 

from reduced emissions of these pollutants? The RIA for the final rule calculated energy 

disbenefits associated with the increase in CO2 emissions, not benefits, because the controls 

would slightly increase electricity use. These disbenefits did not affect the rounded total 

benefits. We added a statement to the preamble and RIA memo to clarify that the energy 

disbenefits do not affect the rounded benefits for this proposal as well.

- Should this sentence refer to “proposed” rule, rather than “final” rule? OK.